Fluorocarbon based fluids have found widespread use in industry in a number of applications, including as refrigerants, aerosol propellants, blowing agents, heat transfer media, and gaseous dielectrics. Because of the suspected environmental problems associated with the use of some of these fluids, including the relatively high global warming potentials (GWP) associated therewith, it is desirable to use fluids having the lowest possible greenhouse warming potential in addition to zero ozone depletion potential (ODP). Thus there is considerable interest in developing environmentally friendlier materials for the applications mentioned above.
Fluorinated butenes having zero ozone depletion and low global warming potential have been identified as potentially filling this need. However, the toxicity, boiling point, and other physical properties in this class of chemicals vary greatly from isomer to isomer. One fluorobutene having valuable properties is cis-1,1,1,4,4,4-hexafluorobutene. Thus, there is a need for new manufacturing processes for the production of hexafluorobutenes and in particular cis-1,1,1,4,4,4-hexafluorobutene:

A key synthetic precursor to this material is the known compound 1,1,1,4,4,4-hexafluoro-2-butyne.
Hexafluoro-2-butyne has been made by the dechlorination of CF3CCl═CClCF3 with zinc in ethanol (J. Am. Chem. Soc., 71 (1949) 298). This process generates zinc salts and co-produces substantial amounts of CF3CH═CClCF3 as well.
U.S. Patent Publication No. 2009/0156869 describes the catalytic dehalogenation of CF3CCl═CFCF3 which gives the desired butyne along with substantial amounts of the hydrodechlorination product, CF3CH═CFCF3.
Thus there is a need to produce the desired alkyne from a suitable precursor in such a way that the formation of substantial amounts of hydrodechlorination by-products (e.g., CF3CH═CXCF3) is avoided.